In the prior art, a plurality of hand-held surgical devices have been proposed which are operable by ultrasonic vibrations to emulsify body tissue. For instance, these devices utilize ultrasonic transducer components which are operable for converting electrical energy to ultrasonic vibrational energy. This vibrating ultrasonic energy is directed to a surgical tip assembly whereby the vibrations are imparted to tissue so as to emulsify the latter. This approach for removing tissue has gained wide-spread acceptance in the surgical field. Devices of this type are described in U.S. Pat. Nos. 3,589,363; 4,223,676; 4,246,902; 4,493,694; and 4,922,902.
In addition, there have been proposed surgical devices which utilize laser energy for removing tissue. One type of laser operated device is a surgical handpiece which is describe in U.S. Pat. No. 4,694,828 to Eichenbaum, wherein a laser beam is directed onto body tissue. The laser beam is effected to vaporize such tissue which is subsequently aspirated from the surgical site.
In the publication entitled "The Nd-YAG Laser in Ophthalmology, Principles and Clinical Applications of Photodisruption", by Steinert et al., the optical breakdown associated with utilization of laser energy is explained. More particularly, optical breakdown is a non-linear effect achieved when laser light is sufficiently condensed in time and space to achieve high irradiance or density of power. During optical breakdown of light energy, an ionized state or plasma is formed. The rapid plasma expansion generates a shockwave which may be followed by cavitation or vapor bubble formation. Collapse of the cavitation or vapor bubbles also contributes to shockwave generation. By focusing laser energy on a target material such as gas, liquid or a solid, damage to the target material may be caused by the sequence of optical breakdown, plasma formation and shockwave generation.
Another type of laser operated surgical device uses a handpiece that carries an optical fiber which delivers laser energy therealong to a surgical tip assembly. In the tip assembly, the laser energy is converted to ultrasonic or acoustical vibrational energy which is then mechanically transmitted by the tip assembly to the tissue that is to be removed. Resulting vibrations emulsify the tissue it contacts. These types of laser operated surgical handpieces are described in U.S. Pat. Nos. 4,729,373 to Peyman and 4,932,954 to wondrazek et al.
In another laser device and as disclosed in U.S. Pat. No. 4,887,600 to watson et al., laser pulses are delivered via an optical fiber to break down stones, calcified tissue or the like. In this device, the distal end of the optical fiber is placed in contact with the material to be broken down.
U.S. Pat. No. 4,608,979 discloses an apparatus which produces focused shockwaves derived from laser energy for the fragmentation of concretions such as kidney stones. In this apparatus, a laser beam is focused in a first position by coupling and focusing means, wherein a shockwave produced by the focused laser beam is then directed to a concretion in a living body.
In systems using laser operated surgical handpieces that transmit laser energy by virtue of an optical fiber through an opening in a tip assembly, clogging of the tip assembly occurs as a result of insufficient emulsification of body tissue which hinders subsequent operation of the handpiece. In addition, prior art techniques that use ultrasonic energy require high amounts of energy which can be transferred to the surgical site and result in surgical complications. In response to these difficulties with prior art devices, a need has developed to provide a surgical method and apparatus for removing body tissue that minimizes potential for surgical complications as well as prevent or minimize system failure by clogging of surgical tip assemblies by partially emulsified body tissue or material.
In response to this need, an improved method and surgical apparatus for removing tissue from surgical sites has been developed which overcome problems associated with prior art devices. The improved surgical apparatus includes a device that uses vibratory motion of a tip driven by means of laser energy optical breakdown to emulsify body tissue. In addition, the device includes irrigating and aspirating means to provide irrigating fluid for emulsification and removal of emulsified material, respectively. The laser energy is transmitted through an optical fiber and focusing means which generate a shockwave to produce vibrational motion in the tip as well as an acoustic resonator which further emulsifies body tissue or material.
Applicants are unaware of any prior art, including the above-listed prior art documents, which teach or suggest a method and surgical apparatus for removing body tissue using laser energy which includes a handpiece comprising a surgical tip assembly that combines laser means for creating optical breakdown and a shockwave to cause vibrations in the tip of the tip assembly and subsequent destruction or emulsification of body tissue.